R/get_metadata_names.R

In USGS-R/laketemps: Lake Temperatures Collected by Situ and Satellite Methods from 1985-2009

#'@title get metadata names in GLTC dataset
#'@description Lake metadata records were compiled for the Global Lake Temperature 
#'Collaboration and can be accessed and returned as data.frames. 
#'See associated publication and references therein for details.
#'@param lake_name a valid name of a lake in the GLTC dataset (see \code{\link{get_lake_names}}).
#'@return a character vector of valid metadata variable names for all lakes. 
#'If \code{lake_name} is specified, only the metadata fields populated for \code{lake_name} 
#'are returned. 
#'@seealso \code{\link{get_metadata}}, \code{\link{get_climate_names}}, \code{\link{get_lake_names}},
#'@importFrom dplyr filter 
#'@examples
#'get_metadata_names()
#'get_metadata_names('Victoria')
#'@export
get_metadata_names <- function(lake_name = NULL){
  
  # -- fix for R CMD check 'no visible binding for global variable'
  siteID <- "_private"
  # -- fix for R CMD check 'no visible binding for global variable'
  
  if (is.null(lake_name)){
    metadata_vars <- names(gltc_metadata)
  } else {
    data <- filter(gltc_metadata, siteID == get_site_ID(lake_name))
    # empty data is '' ##
    u_i <- data[1,] != ''
    metadata_vars <- colnames(data[,u_i])
  }

  return(unique(metadata_vars))
}